Method of setting transmission shift points in real-time based upon an engine performance curve

ABSTRACT

The present invention provides a method for setting a shift point for shifting a transmission for a powered vehicle between a first gear ratio and a second gear ratio. The method includes determining input power data points based on real-time input torque data. The input torque data includes a maximum input torque. The method also includes calculating a gear step value based on the first gear ratio and second gear ratio. The method further includes determining a first power value and computing a second power value based on the gear step value. The first power value and second power value are compared to one another and adjustments are incrementally made in the first power value speed until the difference between first and second power values meets a threshold. The shift point is therefore based on the result of comparing the first power value and the second power value and the corresponding speed associated with the first power value.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/092,470, filed Apr. 22, 2011 entitled “Method of Setting TransmissionShift Points in Real-Time Based Upon an Engine Performance Curve,” thedisclosure of which is expressly incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present invention relates to a method for shifting a motor vehicletransmission having a plurality of automatically selectable gear ranges,and in particular, to a method of setting shift points automatically andin real-time for shifting a transmission in a vehicle.

BACKGROUND

A conventional transmission for a powered vehicle includes software or acontrol scheme for determining when the automatic transmission shiftsfrom one gear range (or ratio) to another gear range. The software orcontrol scheme can include one or more shift schedules for shifting thetransmission. The shift schedule can be an economy or performance shiftschedule, for example, which controls the shifts based on currentdriving conditions.

The transmission controller can communicate with an engine in thevehicle. The engine generally includes an engine controller or enginecontrol module. Data or information related to the engine, includingtorque, power, temperature, pressure, speed, etc., can be communicatedto the transmission controller. This data or information can be used bythe transmission controller for operating the transmission based oncurrent engine conditions.

In particular, each engine is capable of providing power to thetransmission. The engine generally provides different levels of powerbased on engine speed. The power can be illustrated as a performancecurve, for example, in which the power increases to a maximum value. Theshape of a performance curve can be different for different engines andthis can provide challenges to the transmission controller to adapt thefunction of the transmission to different engines. This can beparticularly challenging to adapt shift schedules for shifting thetransmission because the amount of input torque received by thetransmission can be different for each engine.

In the past, most engines made peak power at an engine's full loadgoverning speed. However, today's engine manufacturers are beingrequired to reduce emissions and improve fuel economy. To meet thesedemands, many engines now make peak power at engine speeds less than thefull load governing speed. This approach has many consequences to theperformance of the transmission. In conventional transmission shiftschedules, a transmission would make an upshift (e.g., from anumerically higher gear ratio to a numerically lower gear ratio) nearthe engine's full load governing speed. As noted, this generally was thepoint where an engine produced its greatest amount of power. Ideally,the power after making an upshift should be approximately the same asthe power before making the shift. This provides the best performanceand fuel efficient manner of shifting the transmission.

Due to federal regulations, however, transmission shift schedules mustnow adapt to different engine performance curves. Since each engine canhave its own unique performance curve, transmission shift points can bedifferent for each engine. Thus, shift schedules are dependent on theshape of the engine performance curve and a transmission gear step.Since transmission software must enable a transmission to shiftaccording to any engine performance curve, there is a need for a methodto establish shift points for shifting a transmission according to anyengine performance curve. There is a further need for determining idealshift points automatically and in real-time for each gear step based onany engine performance curve.

SUMMARY

The present invention provides a method for setting a shift point forshifting a transmission for a powered vehicle between gear ratios. In anexemplary embodiment, the method includes determining input power datapoints to the transmission based on input torque data and calculating agear step value based on a first gear ratio and a second gear ratio. Afirst power value is determined at a first speed and a second powervalue is computed at a second speed based on the gear step value. Themethod further includes comparing the first power value to the secondpower value and setting the shift point based on the comparison. Theinput torque data can be received from a data bus, which is electricallycoupled to a transmission controller.

In one form of this method, the gear step can be calculated by dividingthe first gear ratio by a second gear ratio. In another form thereof, adifferent speed value can be determined at the maximum input torque andthen multiplied by the gear step. The resulting speed can be compared toa full load governing speed value of the vehicle. As such, the shiftpoint may be set to approximately the full load governing speed if theresulting speed exceeds the full load governing speed.

Alternatively, the method can include determining a second input speedvalue based on the first input speed value. The determination caninclude dividing the first input speed value by the gear step. Tocompute the second power value, the method can also includeinterpolating between at least two input power data points at the secondinput speed value. As for the comparison step, the method can comprisemultiplying the first power value by a threshold value and determiningif the second power value is equal to or greater than the result ofmultiplying the first power value by the threshold value.

In this embodiment, the method can further include adjusting the firstspeed value if the second power value is less than the result ofmultiplying the first power value by the threshold value. The firstspeed value can be adjusted by a constant value up to a full loadgoverning speed of the vehicle.

In another embodiment, a method is provided for establishing a shiftpoint for shifting an automatic transmission in a powered vehicle duringa full throttle shift from a first gear ratio to a second gear ratio.The method includes receiving input torque data from a data buselectrically coupled to a transmission controller and converting theinput torque data to input power data. A gear step value can becalculated based on the first gear ratio and second gear ratio. Themethod further includes determining a first input speed and first powervalue based on the input torque data and computing a second input speedbased on the gear step value. A second power value can be determinedbased on the second input speed. The method also includes comparing thefirst power value to the second power value and setting the shift pointbased on the result of comparing the first power value to the secondpower value.

In one form of this embodiment, the calculating step can comprisedividing the first gear ratio by the second gear ratio. In another formthereof, the determining a first input speed can include determining anengine speed at a maximum input torque and multiplying the engine speedand gear step. The first input speed value, e.g., the product of theengine speed and gear step, can be compared to a full load governingspeed value of the vehicle. As such, the shift point can be set toapproximately the full load governing speed when the first input speedexceeds the full load governing speed.

In one aspect, the computing a second input speed comprises dividing thefirst input speed by the gear step value. In another aspect of themethod, the determining a second power value can include interpolatingthe input power data at the second input speed. The method can furtherinclude multiplying the first power value by a threshold value anddetermining if the second power value is equal to or greater than theresult of multiplying the first power value by the threshold value. Inaddition, a different aspect of the method can include adjusting thefirst speed value if the second power value is less than the result ofmultiplying the first power value by the threshold value. The firstspeed value can be adjusted by a predetermined value up to a full loadgoverning speed of the vehicle.

An advantage of determining a shift point using the above-describedmethod is being able to optimize a shift schedule for any given powercurve. The shift points can be established in real-time andautomatically set based on information and data shared between theengine and transmission. In particular, shift points can be optimizedfor any engine torque or power curve.

Other advantages include better fuel economy and performance. Inaddition, the method of setting shift points, as described in thepresent disclosure, can assist with reducing emissions and noise levelsby shifting the transmission at lower engine speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present invention and the manner ofobtaining them will become more apparent and the invention itself willbe better understood by reference to the following description of theembodiments of the invention, taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of one embodiment of a transmission coupledto a controller via a wiring harness; and

FIG. 2 is a flow chart of an embodiment for selecting a shift point forshifting a transmission;

FIG. 3 is another flow chart of the embodiment of FIG. 2;

FIG. 4 is another flow chart of the embodiment of FIG. 2;

FIG. 5 is another flow chart of the embodiment of FIG. 2; and

FIG. 6 is another flow chart of the embodiment of FIG. 2.

Corresponding reference numerals are used to indicate correspondingparts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather, the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

The present invention relates to a method for calculating or settingshift points for shifting a transmission in a powered vehicle. Withreference to FIG. 1, an exemplary embodiment of a transmission setup isprovided. A transmission 102 is shown in FIG. 1 with a controller 104,i.e., transmission control module (“TCM”). Software is downloaded to theTCM 104 and a wiring harness 106 couples the TCM 104 to the transmission102. A conventional wiring harness 106 includes an outer plastic bodythat surrounds wires that extend from a TCM connector 110 at one end ofthe wiring harness 106 to a transmission connector 108 disposed at theopposite end of the wiring harness 106.

The wiring harness 106 can also include other connectors such as speedsensor connectors. In FIG. 1, for example, an engine or input speedsensor connector 112 couples to an engine or input speed sensor 126 ofthe transmission 102. Likewise, in an embodiment in which a torqueconverter is present, a turbine speed sensor connector 114 couples thewiring harness 106 to a turbine speed sensor 128 of the transmission102. Also, an output speed sensor connector 116 of the wiring harness106 couples to an output speed sensor 130 of the transmission 102. Otherpossible connectors of the wiring harness 106 include a data busconnector 120, a throttle position sensor (TPS) 124, a vehicle connector118 (e.g., Vehicle Interface Module (“VIM”) connector), and analternative transmission harness mating connector 122. There can beadditional connectors and/or harnesses in other embodiments.

As noted, the transmission 102 can include the engine or input speedsensor 126, turbine speed sensor 128, and output speed sensor 130. Inthis embodiment, the transmission 102 mounts to an engine (not shown) bycoupling a converter housing 134 of the transmission 102 to a flywheelhousing (not shown) of the engine (not shown). A torque-transferringmechanism 132, e.g., a torque converter or fluid coupling, of thetransmission 102 can include a plurality of lugs 140 that couple to aflex plate (not shown) via flex plate bolts (not shown). For purposes ofthis embodiment, the torque-transferring mechanism 132 will be referredto as a torque converter. In some embodiments, a torque converter maynot be present. In these embodiments, an input shaft of the transmission102 is coupled to the engine via a clutch, for example.

In one embodiment, an internal combustion engine (not shown) can becoupled to the transmission 102 via the torque converter 132 (or inputshaft for those embodiments without a torque converter). The internalcombustion engine can be configured to rotatably drive an output shaft(not shown) of the engine that is coupled to the input (not shown) ofthe torque converter 132. The torque converter 132 can further include aturbine (not shown) that is coupled via splines to a turbine shaft (notshown) of the transmission 102. In turn, the turbine shaft (not shown)can be coupled to, or integral with, a rotatable input shaft (not shown)of the transmission 102. An output shaft (not shown) of the transmission102 can be coupled to or integral with, and rotatably drives, apropeller shaft (not shown) that is coupled to a conventional universaljoint (not shown). The universal joint (not shown) can be coupled to,and rotatably drives, a drive axle (not shown) having tires or wheelsmounted thereto at each end. The output shaft (not shown) of thetransmission 102 drives the tires in a conventional manner via thepropeller shaft, universal joint and drive axle.

During operation, as the engine rotatably drives the torque converter132, the engine or input speed sensor 126 detects the rotational speedof the torque converter 132. The torque converter 132 can include ribsor protrusions (not shown) that protrude from the surface of the torqueconverter 132 and which the engine or input speed sensor 126 measuresduring each revolution.

As shown in FIG. 1, the transmission 102 can also include a main case orhousing 136 that encloses a gearbox, i.e., gears, dog clutches, clutchplates and reaction plates, a number of automatically selectable gears,planetary gear sets, hubs, pistons, shafts, and other housings. Thetransmission 102 can further include a turbine shaft (not shown) whichcan rotate various clutches or shafts in the transmission. A gear ortonewheel (not shown) can be coupled to the turbine shaft (not shown)such that the turbine speed sensor 128, which couples to the main caseor housing 136, measures the rotational speed of the gear or tonewheel(not shown). Other transmissions can include alternative ways known tothe skilled artisan for measuring turbine speed.

In one embodiment, the transmission 102 can include an output shaft (notshown) which is enclosed by a rear cover 138 of the transmission 102. Tomeasure the output speed of the transmission 102, the output speedsensor 130 can couple to the rear cover 138. A smaller gear or tonewheel(not shown) can be coupled to the output shaft (not shown) such that theoutput shaft and gear or tonewheel rotate together. The output speedsensor 130 is aligned with the gear or tonewheel and measures therotational speed of the output shaft.

Transmission shift schedules and other related instructions are includedin software which is downloaded to the TCM 104. The TCM 104 can controlthe shifting of the transmission by electrically transferringinstructions to the transmission such that certain actions are carriedout by the clutches, dog clutches, pistons, etc. In one non-limitingembodiment, the TCM 104 is part of a transmission control circuit thatcan further include an electronic solenoid and valve assembly forcontrolling the engaging and disengaging of clutch assemblies, etc.Components within the transmission 102 can be activated electrically,mechanically, pneumatically, automatically, semi-automatically, and/ormanually. The transmission control circuit is able to control theoperation of the transmission to achieve desired performance.

Based on instructions in a transmission software program, thetransmission control circuit (e.g., TCM 104) can select a shift scheduledepending on a vehicle's driving condition and execute instructionscontained in the software by sending signals through the wiring harness106 to control the transmission 102. The TCM 104 can also receivemeasurement data from the transmission 102 such as, for example, inputspeed from the input speed sensor 126, turbine speed from the turbinespeed sensor 128, and output speed from the output speed sensor 130. Inan embodiment in which the transmission does not include a torqueconverter 132, the transmission may only have an input speed sensor 126and output speed sensor 130. The TCM 104 can also calculate variousparameters including transmission gear ratio or range, which istypically the ratio of input speed to output speed. In an embodiment inwhich the transmission 102 has a torque converter 132, the transmissiongear ratio or range can also be determined by the ratio of turbine speedto output speed.

The TCM 104 can also receive accelerator pedal position (i.e., throttlepercentage) from a throttle input source, which can be coupled to anengine control module (ECM) or vehicle control module (VCM) fortransmitting throttle data over a data bus. Examples of a conventionaldata bus include J1587 data bus, J1939 data bus, IESCAN data bus, GMLAN,Mercedes PT-CAN. In addition, a Hardwire TPS (throttle position sensor)to TCM or Hardwire PWM (pulse width modulation) to TCM can be used.Information such as accelerator pedal position that is communicated overthe data bus is not limited to a particular engine/transmissionconfiguration. Instead, the data bus can be adapted to most vehiclesetups.

In the present disclosure, aspects of a method are provided forcalculating or setting shift points for shifting a transmission betweentwo gear ratios. In at least one aspect, an engine having an enginecontroller provides power to a transmission having a transmissioncontroller. Engine data can be transferred or communicated to thetransmission controller over a data bus.

In an exemplary embodiment shown in FIG. 2, a method 200 is provided forsetting a shift point for shifting a transmission between a first gearratio and a second gear ratio. In method 200, a transmission controllercan receive engine data and information from a data bus. For example, inblock 210, the controller receives torque data. In one aspect, thecontroller can receive torque data in the form of a torque curve. Thiscan, for example, be communicated to the transmission controller in theform of an advertised engine torque curve (AETC) in which engine torquedata points are provided in relation to engine speed. In a differentaspect of the present disclosure, torque data can be communicated in theform of a configuration map. In this form, several engine torque datapoints are provided to the controller in relation to engine speed. Oneof the data points can be the peak engine torque and the correspondingengine speed at which this torque is achieved.

In block 220, the controller can convert the torque data into powerdata. This can be achieved by multiplying the torque by the engine speedand then dividing by a constant value. This calculation is as follows:POWER,kW=(TORQUE,N−m)×(ENGINE SPEED,RPM)/9549

In this calculation, the engine speed data is in the form of revolutionsper minute. The controller is capable of making this and othercalculations in a short amount of time, and therefore the shift pointcan determined in real-time. In blocks 230 and 240, the controller alsoperforms additional calculations. In block 230, for example, the firstgear ratio is determined. In this embodiment, the first gear ratio isreferred to as a downshift gear ratio. In other words, if thetransmission is shifting from third gear range to fourth gear range, thedownshift gear ratio is the gear ratio for the third gear range.Likewise, in block 240, the upshift gear ratio is the gear ratio for thefourth gear range. As previously described, the gear ratio can bedetermined by the ratio of input speed to output speed.

Once the calculations in blocks 220, 230, and 240 are completed, thecontroller can compute the transmission gear step in block 250. To doso, the gear step is the ratio of the downshift gear ratio to theupshift gear ratio.

With reference to FIG. 3, the peak engine torque and correspondingengine speed at the peak engine torque can be determined in blocks 300and 310, respectively. In some embodiments, an advertised peak enginetorque and corresponding engine speed at this advertised torque can bedetermined. As previously described, this information can be provided inthe advertised engine torque curve. The peak engine torque can becommunicated to the transmission controller via the data bus. Likewise,the engine speed at which the engine achieves peak torque can becommunicated to the controller via the data bus. The peak engine torque(e.g., advertised peak engine torque) and corresponding speed can beobtained from an engine performance curve or from a configuration map.In either case, the peak torque and corresponding engine speed can bedirectly communicated to the controller.

Once the controller determines the peak engine torque and thecorresponding engine speed at this torque, the controller can performthe operation in block 320 of method 200. In block 320, the controllercan optionally add or subtract a threshold value, “CalA”, to the enginespeed determined in block 310. This optional threshold value can be usedfor tuning purposes. The adjusted engine speed value, i.e., the enginespeed value determined in block 310 adjusted by threshold value “CalA”,is then multiplied by the gear step calculated in block 250. The resultof the calculation in block 320 will be referred to as “SB”.

Once the value of “SB” is known, the controller determines the full loadgoverning speed (“FLGS”) for the engine in block 330. This speed can becommunicated to the controller via the data bus, for example. Once thefull load governing speed, FLGS, is known, the controller can comparethe value of “SB” to FLGS in block 340. If the value of “SB” is greaterthan or equal to the full load governing speed, the controller computesan adjusted full load governing speed in block 350. In other words, thevalue of “SB” is the engine speed or turbine speed at which thecontroller controls the transmission for making the desired shift. Theshift point can be adjusted by reducing the full load governing speed bya threshold value, “CalB”. The value of “CalB” can be 50 RPM, forexample. The value of “CalB” can typically vary between about 0-125 RPM.The shift point can be set in block 370 to the value computed in block350 if the shift point is desired in terms of transmission input speed.Alternatively, if it is desired to set the shift point to transmissionoutput speed, the result of block 350 is then divided by the downshiftgear ratio in block 360 and the shift point is set to the resultcomputed in block 360. In either case, the shift point is determined forshifting the transmission from the downshift gear ratio to the upshiftgear ratio.

The importance of setting the shift point at a slower speed than thefull load governing speed in blocks 350 and 360 is because thetransmission control system requires time for filling clutch(es),releasing clutch(es), reading transmission output speed, and otherfunctions before completing a shift. By initiating the shift at a speedless than full load governing speed, sufficient time can be allocated tothe transmission control system to ensure a smooth shift.

Block 340 is important to method 200 because it can be counterproductiveto shift the transmission at a greater speed than the engine's full loadgoverning speed. Once the engine reaches its full load governing speed,the engine typically pulls back or reduces its output power to thetransmission. In many engine power curves, the amount of output power ortorque produced by the engine is significantly less once the enginereaches its full load governing speed. Engine and transmissionperformance can be negatively affected by setting shift points after theengine achieves its full load governing speed.

If the condition set forth in block 340 is not satisfied, method 200continues to block 400 as shown in FIG. 4. In block 400, thetransmission controller determines the engine power at the engine speed“SB”. This power, referred to as “PB”, can be determined byinterpolating the engine power curve if this information is communicatedto the controller. Alternatively, if only several engine torque datapoints are communicated to the controller, the controller interpolatesbetween this data to find the engine power at speed “SB”. As describedabove, if the engine performance data communicated to the controller istorque, the controller can convert torque to power for interpolating inblock 400.

Once engine power “PB” is known, the controller can divide engine speed“SB” by the calculated gear step to determine engine speed “SA” in block410. Once engine speed “SA” is known, the controller can again determinethe engine power “PA” at engine speed “SA”. In block 420, for example,the controller can interpolate the engine power curve to determine theengine power “PA”. Alternatively, if data is in the form of aconfiguration map, the controller may have to interpolate between twodifferent torque or power data points to determine the value of “PA”.

The values of “SA”, “SB”, “PA”, and “PB” are important for setting theshift point between the downshift gear ratio and upshift gear ratio.“SB” refers to the engine speed before the shift and “SA” refers to theengine speed after the shift. Similarly, “PB” refers to engine powerbefore the shift and “PA” refers to engine power after the shift. Asdescribed above, to maximize vehicle and transmission performance, itcan be important to set transmission shift points such that the powerafter the shift is about the same as the power before the shift. Thus,method 200 provides a real-time process for automatically determiningthe engine power and corresponding speed before and after a shift.

Referring to block 430, once the values of “PB” and “PA” are known, thecontroller can perform a comparison of the two values. As shown in FIG.4, the value of “PA” can be compared to the value of “PB”. A tolerancevalue, CalC, can be included in the comparison. The value of CalC is apercentage and can be any desirable value. In one embodiment, the valueof CalC is between 75-100%. In a different embodiment, the value of CalCis between 90-100%. In another embodiment, the value of CalC isapproximately 95%.

When there is no tolerance incorporated in the comparison of block 430,the value of CalC is 100%. As described above, it is desirable for thepower after the shift to be approximately the same as the power beforethe shift. This enables vehicle performance to be maximized. If thecondition set forth in block 430 is satisfied, i.e., the value of “PA”is greater than or equal to the value of “PB” multiplied by thetolerance value CalC, method 200 proceeds to block 500 in FIG. 5.

With reference to FIG. 5, the shift point is set for shifting thetransmission from the downshift gear ratio to the upshift gear ratio. Inblock 500, the value of “SB” can be reduced by another threshold ortolerance value, CalD. The threshold or tolerance value, CalD, serves asimilar purpose as threshold value, CalB as described above. The timingof shifting between two gear ratios includes considerations such as thetime for filling clutch(es), releasing clutch(es), reading transmissionoutput speed, etc. It can be important for optimal shift quality thatthe transmission clutches begin being applied or released before theengine speed is pulled down during the shift. For this reason, theengine speed value, “SB”, is reduced by CalD so that the start of theshift occurs before the engine is pulled down to complete the shift.

The shift point for shifting from the downshift gear ratio to theupshift gear ratio occurs at the adjusted engine speed value calculatedin block 500. In block 510, the adjusted engine speed value calculatedin block 500 can be optionally divided by the downshift gear ratiopreviously calculated in block 230. This calculation in block 510 is notrequired, and the result of this calculation converts the shift pointfrom engine speed to transmission output speed. In some applications,the shift point is preferred to be referenced in transmission outputspeed, whereas in other applications the shift point is preferred interms of engine speed. In either case, the shift point is calculated inblock 500 and optionally block 510. Once the shift point is determined,it is programmed into a full throttle shift schedule, for example, inblock 520. The shift point can be referenced in terms of engine speed,turbine speed, or transmission output speed. Note that a full throttleshift schedule is only provided as a non-limiting example, as it may bepossible to determine shift points in real-time for other types of shiftschedules including economy and/or performance shift schedules.

Returning to FIG. 4, if, however, the condition set forth in block 430is not satisfied, method 200 proceeds to block 600 (see FIG. 6). In thiscase, the controller determines that the power after the shift is notsubstantially the same as the power before the shift. In this event, thecontroller can incrementally increase the value of “SB” by a constantvalue such as 25 RPM. The constant value, however, can be set at anydesirable value and is not limited to 25 RPM.

Once “SB” has been incrementally changed, the controller compares thenew value of “SB” to the full load governing speed in block 610. Thecomparison in block 610 is similar to the comparison performed in block340. If the value of “SB” exceeds or is equal to the full load governingspeed, method 200 proceeds to block 350. The shift point can bereferenced in terms of engine speed, turbine speed, or transmissionoutput speed. If, however, the condition set forth in block 610 issatisfied, i.e., the value of “SB” is less than the full load governingspeed, the controller determines the value of “PB” in block 400. Asdescribed above, once the value of “PB” is determined in block 400, thevalues of “SA” and “PA” are determined in blocks 410 and 420,respectively. The comparison in block 430 can be repeated for the newvalues of “PA” and “PB”, and if the condition set forth in block 430 issatisfied, the shift point can be set in block 520. Alternatively, ifthe condition set forth in block 430 is not satisfied, the controllercan incrementally adjust the value of “SB” in block 600 and repeat thecomparison of block 610.

The value of “PA” and “PB” may converge such that the condition setforth in block 430 is satisfied. In this case, the desired set point forshifting the transmission between the downshift gear ratio and upshiftgear ratio is determined. However, in some instances, the shape of theengine power curve or the size of the gear step may be such that thevalues of “PA” and “PB” do not converge and the condition set forth inblock 430 cannot be satisfied. In this case, the value of “SB” willlikely be equal to or greater than the full load governing speed and thetransmission shift point can be set according to block 370. In otherwords, if the condition set forth in block 430 is never satisfied, thecontroller can set the shift point to the full load governing speedadjusted by any tolerances for shift quality.

Although the above-described embodiments have been described withreference to shifting from a downshift gear ratio to an upshift gearratio, one skilled in the art can appreciate that the method can beincorporated for other shifts. For example, it may be possible toperform a similar method for setting shift points for a downshift from anumerically lower gear ratio to a numerically higher gear ratio. In thiscase, CalC would typically be greater than 100%.

Also, while not shown in method 200, the controller can also determinethe accelerator pedal position (i.e., throttle position or percentage)and determine whether shift points can be determined according to method200. In an exemplary embodiment, for example, method 200 can only beused for setting shift points for shifting the transmission between anumerically higher gear ratio to a numerically lower gear ratio at fullor 100% throttle. For purposes of the present disclosure, full throttle(FT), wide open throttle (WOT), or 100% throttle refer to theaccelerator pedal being fully applied. Alternatively, closed throttle(CT) or 0% throttle refers to the accelerator pedal not being applied(e.g., the vehicle is coasting or braking). In an inbetween condition,the accelerator pedal position can be referred to as partial or partthrottle (PT) where the pedal is partially being applied. In variousembodiments, method 200 may be applicable for full, closed, and/orpartial throttle shifts.

While exemplary embodiments incorporating the principles of the presentinvention have been disclosed hereinabove, the present invention is notlimited to the disclosed embodiments. Instead, this application isintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

The invention claimed is:
 1. A method of setting a shift point forshifting a transmission in a powered vehicle between a first gear ratioand a second gear ratio, the transmission having a controllerelectrically coupled to a data bus and the vehicle having an engineelectrically coupled to the data bus, comprising: (a) receiving inputtorque data from the data bus, the input torque data including a maximuminput torque at an engine speed value; (b) calculating input power databased on input torque data; (c) calculating a gear step value based onthe first gear ratio and second gear ratio; (d) computing a first speedvalue based on the engine speed value and gear step value; (e) computinga second speed value based on the first speed value and gear step value;(f) determining a first input power and a second input power from theinput power data, the first input power corresponding to the first speedvalue and the second input power corresponding to the second speedvalue; (g) comparing the first input power and the second input power toone another; and (h) setting the shift point based on the result ofcomparing the first input power and the second input power.
 2. Themethod of claim 1, wherein step (c) comprises dividing the first gearratio by the second gear ratio.
 3. The method of claim 1, furthercomprising comparing the first speed value to a full load governingspeed value of the vehicle.
 4. The method of claim 1, wherein step (h)comprises setting the shift point to approximately the full loadgoverning speed when the first speed value exceeds the full loadgoverning speed.
 5. The method of claim 1, wherein step (e) comprisesdividing the first speed value by the gear step value.
 6. The method ofclaim 1, wherein step (f) comprises interpolating between at least twovalues of the input power data at each speed value.
 7. The method ofclaim 1, wherein step (g) comprises: (i) multiplying the first inputpower by a threshold value; and (j) determining if the second inputpower is equal to or greater than the result of step (i).
 8. The methodof claim 7, further comprising adjusting the first speed value if thesecond input power is less than the result of multiplying the firstinput power by the threshold value.
 9. The method of claim 8, whereinthe first speed value is adjusted by a constant value up to a full loadgoverning speed of the engine.
 10. The method of claim 9, furthercomprising repeating steps (e)-(h) if the second power value is lessthan the result of step (i).
 11. The method of claim 9, furthercomprising repeating steps (e)-(h) until the second power value is equalto or greater than the result of step (i).
 12. The method of claim 9,wherein step (h) comprises setting the shift point to the lesser of afull load governing speed and the first speed value corresponding to thesecond power value being equal to or greater than the result of step(i).